Studies on the role of plasma proteins in platelet adhesion and thrombus formation are under way for the present grant. In this renewal proposal, fatty acids are focused as an important factor involved in the interface induced thrombosis. Numerous studies have been directed towards the effect of fatty acids on blood clotting with the lack of mechanistic evaluation and systematic approaches. Although attempts have been made to define the role of fatty acid in the platelet aggregation and hypercoaguability, little work has been done especially related to the thrombogenicity on the artificial and blood vessel surfaces. In this application, we propose to: 1. Investigate whether initial thrombus formation at polymer or natural blood vessel interface is induced and/or accelerated by adsorbed fatty acid. 2. Determine if the subsequent release of absorbed fatty acid, which results in high concentration of the fatty acid at the interface, can induce platelet aggregation. 3. Determine possible endothelial cell damage caused by adsorbed fatty acid via in vitro and in vivo animal experiments. 4. Characterize binding constants of fatty acid to plasma albumin. 5. Correlate physiochemical properties of fatty acid suspension with platelet aggregation. It is expected that the results obtained will be valuable in understanding the phenomenon of blood vessel damage, occlusive vascular disease and atherosclerosis and also in the design of hemocompatible materials.